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      1 /*
      2  * Copyright (C) 2015 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 package com.android.launcher3;
     17 
     18 import android.animation.Animator;
     19 import android.animation.ObjectAnimator;
     20 import android.content.res.Resources;
     21 import android.graphics.Canvas;
     22 import android.graphics.Color;
     23 import android.graphics.Paint;
     24 import android.graphics.Rect;
     25 import android.graphics.drawable.Drawable;
     26 
     27 /**
     28  * The fast scroller popup that shows the section name the list will jump to.
     29  */
     30 public class BaseRecyclerViewFastScrollPopup {
     31 
     32     private static final float FAST_SCROLL_OVERLAY_Y_OFFSET_FACTOR = 1.5f;
     33 
     34     private Resources mRes;
     35     private BaseRecyclerView mRv;
     36 
     37     private Drawable mBg;
     38     // The absolute bounds of the fast scroller bg
     39     private Rect mBgBounds = new Rect();
     40     private int mBgOriginalSize;
     41     private Rect mInvalidateRect = new Rect();
     42     private Rect mTmpRect = new Rect();
     43 
     44     private String mSectionName;
     45     private Paint mTextPaint;
     46     private Rect mTextBounds = new Rect();
     47     private float mAlpha;
     48 
     49     private Animator mAlphaAnimator;
     50     private boolean mVisible;
     51 
     52     public BaseRecyclerViewFastScrollPopup(BaseRecyclerView rv, Resources res) {
     53         mRes = res;
     54         mRv = rv;
     55         mBgOriginalSize = res.getDimensionPixelSize(R.dimen.container_fastscroll_popup_size);
     56         mBg = res.getDrawable(R.drawable.container_fastscroll_popup_bg);
     57         mBg.setBounds(0, 0, mBgOriginalSize, mBgOriginalSize);
     58         mTextPaint = new Paint();
     59         mTextPaint.setColor(Color.WHITE);
     60         mTextPaint.setAntiAlias(true);
     61         mTextPaint.setTextSize(res.getDimensionPixelSize(R.dimen.container_fastscroll_popup_text_size));
     62     }
     63 
     64     /**
     65      * Sets the section name.
     66      */
     67     public void setSectionName(String sectionName) {
     68         if (!sectionName.equals(mSectionName)) {
     69             mSectionName = sectionName;
     70             mTextPaint.getTextBounds(sectionName, 0, sectionName.length(), mTextBounds);
     71             // Update the width to use measureText since that is more accurate
     72             mTextBounds.right = (int) (mTextBounds.left + mTextPaint.measureText(sectionName));
     73         }
     74     }
     75 
     76     /**
     77      * Updates the bounds for the fast scroller.
     78      * @return the invalidation rect for this update.
     79      */
     80     public Rect updateFastScrollerBounds(BaseRecyclerView rv, int lastTouchY) {
     81         mInvalidateRect.set(mBgBounds);
     82 
     83         if (isVisible()) {
     84             // Calculate the dimensions and position of the fast scroller popup
     85             int edgePadding = rv.getMaxScrollbarWidth();
     86             int bgPadding = (mBgOriginalSize - mTextBounds.height()) / 2;
     87             int bgHeight = mBgOriginalSize;
     88             int bgWidth = Math.max(mBgOriginalSize, mTextBounds.width() + (2 * bgPadding));
     89             if (Utilities.isRtl(mRes)) {
     90                 mBgBounds.left = rv.getBackgroundPadding().left + (2 * rv.getMaxScrollbarWidth());
     91                 mBgBounds.right = mBgBounds.left + bgWidth;
     92             } else {
     93                 mBgBounds.right = rv.getWidth() - rv.getBackgroundPadding().right -
     94                         (2 * rv.getMaxScrollbarWidth());
     95                 mBgBounds.left = mBgBounds.right - bgWidth;
     96             }
     97             mBgBounds.top = lastTouchY - (int) (FAST_SCROLL_OVERLAY_Y_OFFSET_FACTOR * bgHeight);
     98             mBgBounds.top = Math.max(edgePadding,
     99                     Math.min(mBgBounds.top, rv.getHeight() - edgePadding - bgHeight));
    100             mBgBounds.bottom = mBgBounds.top + bgHeight;
    101         } else {
    102             mBgBounds.setEmpty();
    103         }
    104 
    105         // Combine the old and new fast scroller bounds to create the full invalidate rect
    106         mInvalidateRect.union(mBgBounds);
    107         return mInvalidateRect;
    108     }
    109 
    110     /**
    111      * Animates the visibility of the fast scroller popup.
    112      */
    113     public void animateVisibility(boolean visible) {
    114         if (mVisible != visible) {
    115             mVisible = visible;
    116             if (mAlphaAnimator != null) {
    117                 mAlphaAnimator.cancel();
    118             }
    119             mAlphaAnimator = ObjectAnimator.ofFloat(this, "alpha", visible ? 1f : 0f);
    120             mAlphaAnimator.setDuration(visible ? 200 : 150);
    121             mAlphaAnimator.start();
    122         }
    123     }
    124 
    125     // Setter/getter for the popup alpha for animations
    126     public void setAlpha(float alpha) {
    127         mAlpha = alpha;
    128         mRv.invalidate(mBgBounds);
    129     }
    130 
    131     public float getAlpha() {
    132         return mAlpha;
    133     }
    134 
    135     public int getHeight() {
    136         return mBgOriginalSize;
    137     }
    138 
    139     public void draw(Canvas c) {
    140         if (isVisible()) {
    141             // Draw the fast scroller popup
    142             int restoreCount = c.save(Canvas.MATRIX_SAVE_FLAG);
    143             c.translate(mBgBounds.left, mBgBounds.top);
    144             mTmpRect.set(mBgBounds);
    145             mTmpRect.offsetTo(0, 0);
    146             mBg.setBounds(mTmpRect);
    147             mBg.setAlpha((int) (mAlpha * 255));
    148             mBg.draw(c);
    149             mTextPaint.setAlpha((int) (mAlpha * 255));
    150             c.drawText(mSectionName, (mBgBounds.width() - mTextBounds.width()) / 2,
    151                     mBgBounds.height() - (mBgBounds.height() - mTextBounds.height()) / 2,
    152                     mTextPaint);
    153             c.restoreToCount(restoreCount);
    154         }
    155     }
    156 
    157     public boolean isVisible() {
    158         return (mAlpha > 0f) && (mSectionName != null);
    159     }
    160 }
    161